Lynx Multi Cart

[SainT]

Ouch. I know what you mean with assembling small chips. That was the main reason why I stopped doing devflash units.

 

On the other hand if the amount of carts go over 100 pieces you can order the carts assembled and smd soldered for a decent price (99 USD's). I am going that route in the programmers forum using a company called Tinysine.

 

Yes, that is a good plan! I've been using Tinysine for quite a while for my PCB's, and have looked at their assembly prices, and they are very good value. I'm not overly keen on getting people to pay anything upfront incase anything goes wrong, so the only other option would be to pay upfront for production, and not knowing what the results are going to be like has made me hesitant to try. I'd be very interested to hear how you get on -- would certainly give me more confidence for future production runs.

[GemInEyeTwin]

This would be so cool to have for my Atari Lynx.

 

SainT,

I am very impressed with the progress you have made since starting this post last year, especially with other commitments.

 

I will certainly be following your progress.

 

All the best!

[johannesmutlu]

Yeah, you will be able to load as many ROM images as you can fit on an SD card. So certainly every Lynx game ever made. The only issue will be sorting out the different ways of accessing 1MB images and save game information as there was no standard method of doing this.

 

I've given some thought to powering off the Lynx via the cartridge pins, but I'm pretty sure that it wont work. As soon as you lose power I believe you have to power it back on again.

 

So I have another cunning plan to get around it.

hi, i wonder what your cunning plan is to get around that hard reset issue,my idea is to externally route pin 31 to pin 33 trough a special cart board and an os controlled special chip wich leads pin 31 to 33 once needed to achief a hard reset effect,in order to being able to select a game from the os menu,if that doesn't work,then we should hack those commercial games by stripping of their first few 100 bytes wich are the encryption bootrom code,and interfaced those roms with the os menu,and let the os menu has it's own bootrom encrytion code instead,this to avoid the lynx to have to do a hard reset constandly.

if rom hacking becomes to tadiouse,then we could let the os menu alway's skips the first few 100 bytes from each rom,to get around this,also since the sd card has a slow transfer speed,it's more naccesarry to have the bootrom encryption code loaded from the flashcard from the os menu instead,the sd card should be only used for loading the roms without the encryption code or the encryption code should be skipped by the os menu.

if high speed transfer is required anyway, then we can use a cf flash card to get around the low speed.

mega pak 1 proves that multi roms are possible on the lynx.

[johannesmutlu]

Had a bit of time to do some messing with the Lynx and the time between successive reads is too quick (about 1.1 microseconds) to be clever about it any try and stream the data directly from the SD card to the Lynx. So I've given up on that train of thought.

 

I've also checked the boot sequence and you can happily cover a load of address / data lines on the cart with a bit of paper and turn the Lynx on and you get "Insert Game". If you remove the bit of paper the game then loads. So this sorts my bootup issue, just isolate the Lynx bus from the SRAM with some bus transceivers and program the SRAM with the micro, then allow the Lynx access to the SRAM when done.

 

So next it's down to picking a microcontroller.

hi, i may have the solution for the sd card issue on the lynx not sure,you mentioned that the lynx reads the sd card way too fast sothat the sd card has simply no time to transfer it's data to the lynx,i suppose it's the encryption security code the lynx has to read in no time right?,if that's the problem,then i was thinking,why not try to develope an os menu with the encryption code on it, installed on the flashcard,sothat the lynx could read the encryption code immediately from the flashcard during startup,those games on the sd card should be hacked withe the encryption code stripped off,or the os menu should be able to skip the first few 100 bytes from each rom,these first few 100 bytes are the encryption code,however if the lynx has to read everything from start to finish quick,then we have to get stick with a cf flashcard since it has 10 times the transfer speed of an sd card.

also speaking of multi roms,mega pak proves that (homebrew)multi roms are possible,games like chopper x and lynxscetth are also in saperate form.

i hope this info will courage you to contineu on your experiment on it,good luck,.

[Shawn Jefferson]

I think you are misunderstanding some fundamental things. There is no reason to hack any games, no reason to remove any encryption. The issue with SD card speed is likely that the Lynx is reading one byte a time from the "cartridge", and it expects the next byte to be available pretty much immediately, and that's not just for encryption, it's for any data load from cartridge.

 

Saint has a working prototype already as he mentioned using flash memory.

[johannesmutlu]

Speaking about the atari lynx aidin pin for bankswitching, what if want want to make a game as huge as let's say

16MB for example, then i was thinking of reusing those adress lines over and over again everytime you excite to another world in a game by switching the audin pin back and forward once needed, the gameboy use this mwthode to contstandly reuse the same adress line for new data once needed.

[SainT]

With the cart, you'd just load another set of data into the cartridge space and then reload from the existing address space.

Edited October 25, 2019 by SainT

[jbserra]

My excitement is killing me. SainT, what's your targeted completion date?

[SainT]

Sadly life is getting in the way of any free time, much post release bug fixing going on at the moment, so work is still hectic.

[johannesmutlu]

so if i have it right, the lynx may cannot reboot itself from the hardware, but if it can be rebooted from the game card with special hardware on it, like a chip wich can route pin 31 to pin 33 anytime you select a game trough an os menu,that would be great.trough i suppose that by rebooting the system, also the required bootstrap rom gets rebooted,but what if There's no way of rebooting the lynx,then we could hack those roms with the bootstrap removed and instead only let the os menu do have it's own bootstrap sothat when you select a game, it only needs to soft reset itself to load your selected game,but what if hacking becomes complex, then make the os menu to let it alway's skip the 1st 512 bytes from each game you select, since those 512 bytes are the bootstrap rom,also i suppose that only the bootstrap rom needs to be readed fast and not the entire rom, so if let's say if the flashcard along it's os software will have it's own startup bootstrap while those roms on the sd card has the bootstrap removed or being skipped by the os menu, then it should be no problem to load roms from the sd card from it, also even if not all parts of the ram are fully resetible , then we can make the os menu as small as it can and only load it on the resetible part of the ram sothat it can refresh itself with the selected game, anyway, it doesn't much matter aslong there will be a way to achieve a multi rom card or sd card, in fact i readed about an upcoming micro sd card xcard adaptor for the lynx being in prototype form.

[7800fan]

Cutting line between pin 31 and 33 would shut Lynx down. It is possible to ghetto reboot by having a solid state relay with N.C. contact between 31 and 33. When it needs a reboot, it energizes the relay which would open contact, cause Lynx to lose power.

 

But there's no way to make it self-turn on after cutting power.

[SainT]

You cant hardware reboot the Lynx. If you want to reboot, just jump to the boot ROM. So I have no issue loading up a new ROM and rebooting from the menu. If you then want to play a different ROM simply turn off and on again, and you're back in the menu.

[johannesmutlu]

I think there are 3 methodes to allow multi roms to be possible on the lynx.

1 by externally connect pin 33 to pin 31 via hardware on the cart to force a reboot .

2 by removing the bootstrap rom from each rom and let the os menu have it's own bootstrap rom instead.

3 or let the os menu allway's skips the first 512 bytes from each game because the first 512 bytes are the bootstrap rom code,instead the os menu should have it's own bootstrap rom, this will also solves the problem of the lynx reading the bootstrap rom from a sd cart too fast because instead it just should read the bootstrap from the flashcard while only the game should be readed from the flashcard, this way a sd flashcard for the lynx should be possible for the lynx, right?!!

[johannesmutlu]

There must by 3 possible way's of making multi roms and but also a sd flashcard possible on the lynx.

1 by externally connecting pin 33 to pin 31 trough hardware on the cart being controlled by the os menu in order to force a reboot ,or

2 be letting the os menu alway's skipping the 1st 512 bytes (wich are the bootstrap) from each rom but the ios menu should,ve it's own bootstrap rom instead,this will also solve the way too quick reading issue of reading the bootstrap from the sd cart because it's noe readed from the flashcard instead.

3 again the os menu should,ve it's own bootstrap rom,but this time the roms should be moddified with the bootstrap removed to get interfaced with the os menu, and to avoid reading issues from the sd card and to avoid rebooting,

For what i know, an xcart wich works with micro sd card exists in prototype form but i don't know if it uses one of these tricks to make multi roms possible on the lynx, but either way it would be great,

[+remowilliams]

...

 

 

I think you are misunderstanding some fundamental things.

 

 

[7800fan]

Connecting 31 and 33 lets power through to the power on switch circuit. If you cut it even to force a reboot, it'd just cause lynx to shut down completely and you would need to manually press ON again. So not a true reboot.

[johannesmutlu]

I think you are misunderstanding some fundamental things. There is no reason to hack any games, no reason to remove any encryption. The issue with SD card speed is likely that the Lynx is reading one byte a time from the "cartridge", and it expects the next byte to be available pretty much immediately, and that's not just for encryption, it's for any data load from cartridge.

 

Saint has a working prototype already as he mentioned using flash memory.

Hi, if speed of the sd cart is the issue, then howabout an cf flashcard solution? Cf flashcards are way bigger then sd cards but has 10 times the transfer speed of sd cards, i knows a flashcard for the lynx does exist,but it's generally meant for game developers and you can only stick 1 game one it, i wish to have a lynx cart wich works with cf flash cards to store commercial and homebrew games on it, trough i readed about a prototype x cart wich works with micro sd cards but i can't find any picture of it, mmm oh well i guess it should only work with sandisk ULTRAS SPEED sd micro cards.

[SainT]

I'm getting more and more confused by these posts. I'll try again --

 

I have a working solution. It uses SRAM to store the cartridge image which is loaded from memory card using a PIC micro. Three is no problem rebooting, I simply just page in the boot ROM and jump to it.

 

I have a physical PCB. In my Lynx. It works.

Edited October 25, 2019 by SainT

[7800fan]

I'm getting more and more confused by these posts. I'll try again --

 

I have a working solution. It uses SRAM to store the cartridge image which is loaded from SD card using a PIC micro. Three is no problem rebooting, I simply just page in the boot ROM and jump to it.

 

I have a physical PCB. In my Lynx. It works.

 

Woot! Picture please??

 

[BadPricey]

@SainT your working version is obviously wrong. I suggest you throw it in the bin and start one of the other methods being suggested.

 

@7800fan pic is of St.Ives in Cornwall UK

 

Sorry I'm bored

BadPricey

[SainT]

Here you go! There will likely be another pcb revision yet to tidy things up a bit, but this is working.

 

I may even provide some kind of abs plastic shell over the chips as an optional extra as I've bought myself a 3D printer since I stared the project.

 

The coloured cable is the icsp cable for the pic micro, by the way. It won't be on the production units...

Edited June 5, 2015 by SainT

[Hyperboy]

@SainT..Looking good my man!

[GadgetUK]

Looking good! But we've yet to work out how to deal with encryption and rebooting the ROM

: o )

 

Groundhog Day!

Edited June 5, 2015 by GadgetUK

[Emehr]

Very cool! Thanks for sharing! I'm looking forward to this.

[+karri]

I am so confused about this thread.

 

SRAM is fast. The ROM can be paged in and a jump there does the reset. SainT has a working prototype. Am I missing something here?